<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
</head>

<body>
    <div id="app">
        <input type="button" value="toggle" @click="flag=!flag">
        <!-- 需求:点击按钮,让 h3 显示,再点击,让 h3 隐藏 -->
        <h3 v-if="flag">这是一个H3</h3>
    </div>
    <script>
        var vm = new Vue({
            el: '#app',
            data: {
                flag: false
            },
            methods: {

            }
        })
    </script>
</body>

</html>